The present invention is concerned with a safety helmet for motor-cyclists that satisfies the special demands made upon this type of head gear, to an extent never achieved before. Simple helmets have been in general use for a long time, and consist essentially of a hard shell covering the cranium and the temples reaching just above eye level, and have a soft padding. These simple helmets may be used, in practically the same design for a wide range of purposes, as crash helmets, safety helmets, workmen's "hard hats", etc. There have also been developed a number of special helmets for particular purposes, such as helmets for hockey, football or rugby players, auto racing drivers, and aviators, to cite just a few examples. All of these special helmets must meet the particular requirements essential only for their particular intended use. For example, a special feature of football and rugby helmets is that they must leave the face of the player free as much as possible in order to afford him the widest possible field of vision, as well as to show his face to the spectators. Less important in such cases is the considerable time required to put on and fit the helmet.
The following features satisfy some of the special requirements of safety helmets for motor-cyclists that are not required of any other type of protective head gear. First of all, no other kind of helmet is exposed to wind velocities of anywhere near the same magnitude. Similarly, the wearer of the helmet faces great danger in case of an accident, due to the high speeds. On the other hand, the wearer does not require an equally wide field of vision extending to nearly 360.degree., as does a rugby player. For these reasons, it is expedient and warranted to encase the head of the wearer, including the full face plus the mouth, nose, cheeks, and chin, in a helmet that is padded all over and in which only a frontal opening for the face has been left, this opening being formed by a transparent visor. Protective helmets of the type that encase the entire head and extend downward so as to cover the chin, are known as "integral helmets" and are gaining increased acceptance because of their excellent protective features even in very serious accidents against which other helmets do not offer any protection, or only minimal protection, although there does exist certain considerable drawbacks to these helmets.
These disadvantages have largely to do with the aforementioned high travel speeds to which a helmet and its wearer may be exposed. The velocities tend to make the helmet slip out of place if it is not made to fit the head of the wearer very exactly and tightly, thereby causing discomfort to the wearer. Heretofore it has not been fully possible, because of technical and commercial reasons, to meet this requirement of a close fit of the wearers' head not only with respect to size, but also shape. A product of such general use would be uneconomical to keep in stock, since it requires a complete line of head sizes and at least four different head shapes ranging from angular and broad to slim and oval.
An even greater disadvantage arising from the requirement of a perfect fit of an integral helmet lies in the fact that a helmet that meets this requirement completely can only be put on and taken off by overcoming the resistance of the elastic padding, since the helmet tapers off downwardly and forwardly to conform to the anatomy of the human head. While this presents a minor problem for healthy uninjured persons, it becomes quite difficult in the case of neck injuries that are unavoidable even with the best protective helmet. In such cases, it is highly important that the helmet be lifted off the head of an injured person as carefully as possible, and this cannot be done with the known integral helmets for the aforementioned reasons. This difficulty is so serious that for some time, all ambulances have been equipped with bone saws, not because it is necessary to saw off a bone at the scene of an accident, but solely for the purpose to remove, where necessary, an integral helmet from the head of the accident victim without injury to him. Obviously, the task of removing the helmet cannot be left to laymen, nor even to highly skilled persons, including doctors, if they are not provided with the necessary special saws. As a result, valuable time may be lost in many cases before the medical care of an accident victim can be initiated.
The present invention is concerned with a motor-cycle helmet that has all the advantages of the known integral helmets, namely their excellent protection in case of an accident, but avoids all of the drawbacks that have not been overcome so far. Thus, the motor-cycle helmet in accordance with the invention makes possible an exact fitting of the head size of the wearer as well as its shape, requiring a considerably smaller number of helmets to be kept in stock, and facilitating an easy and gentle removal, never achieved before, from the head of the wearer. Even in the case of serious injuries to the spine, any further harm to the victim due to the removal of the helmet is positively prevented.
The advantages in accordance with the invention are achieved by designing a protective helmet, generally familiar, to enclose the entire head of the wearer, including his face, and extending downward below the lower edge of the chin, and provided with a visor type of opening for the face that tapers off downwardly. The inside of the helmet is padded using a system, the principle of which is known as such in other contexts, of inflatable air-cushions that are inter-connected by throttling passage-ways. This system differs in many respects from the known systems of air-cushions with inter-connected throttling passage-ways in design, in the manner of its fastening to the helmet, and also by its interaction with other padding features of the helmet.
An essential characteristic of the invention lies in the fact that, while the air-cushion system encloses and protects the neck and cheeks of the wearer, it leaves free the top of the skull, in contrast to all known safety helmets that use inflatable air-cushions, and assigns the protection of the cranium entirely to a familiar padding with an elastic material such as styropor and/or foam rubber. This does not impair the protection in the area of the cranium, but offers the special advantage of eliminating undesirable and often unavoidable upward pull on the chin-strap.
Another advantage achieved by omitting air-cushions above the cranium consists in avoiding the recoil effect that occurs after the end part of an impact due to the re-expansion of the air-cushion.
In accordance with this invention, the air cushions are arranged in the helmet in such a way that they extend from the lower edge of the cheek-bones to the uppermost tip of the ears, but not as far as the temple.
Preferably, the air-cushion system with throttling passage-ways between the various air-cushions, is designed as a continuous band made up of two foils, which are superimposed and inter-connected in a gas-tight manner. Similarly, in accordance with another preferred embodiment of the invention, cross-pieces, likewise made of elastic gas-tight material may be mounted on the upper, lower and lateral edges. This latter embodiment of the invention has the advantage, compared to the simpler embodiment, that the air-cushion will not bulge forward when inflated, and thereby exert an undesirable pressure. The width of these cross-pieces should amount to not less than half the difference between the inside diameter of the helmet and the diameter of the smallest head-size to be fitted, and not greater than three times the amount of that difference.
A preferred design of the air-cushion system consists of a double-walled gas-tight band with perhaps elastic crosspieces between the walls, and containing, in the cervical region and in the two regions of the cheeks, inflatable air-cushions. Between the inflatable air cushions are two non-inflatable parts of the band. The non-inflatable parts of the band have passageways leading to the adjoining inflatable cushion parts. In addition, throttling passage-ways are provided between each air cushion and its adjoining non-inflatable section, said throttling passage-ways affording a pressure balance between the various aircushions, but also retarding the air from the air cushions. The intensity of the retarding effect must be regulated rather carefully. If it is too weak, the air-cushion system does not develop sufficient elasticity and thus does not provide sufficient protection; if it is too strong, the fitting of the helmet to the size and shape of the head of the wearer is impaired.
An ideal throttling effect that is neither too weak nor too strong can be achieved in accordance with a preferred embodiment of the invention by affixing labyrinth joints to the throttling passage-ways. These labyrinth joints can be made most effectively by using some, preferably not more than two, welded or adhesive seams that are staggered and placed adjacent to each other.
Advantageously, the lateral, or cheek, cushions of the system extend no farther forward than to the sides of the chin, while the chin region of the helmet is lined with a familiar non-inflatable pliable cushioning material, for instance styropor or foam rubber. In this way, any undesirable horizontal pull during inflation of the cushion-system is avoided. The same purpose is served by designing an air-cushion that protects the neck, e.g., by installing some welded joints so that it will be inflated less than the cheek cushions, when the system is inflated.
It is also advantageous to have the neck support consist not of an inflatable air-cushion, but of elastic foam material, in the conventional manner.
The fastening of the air-cushion system within the helmet may be done advantageously by placing it inside a pocket that is firmly attached to the helmet and preferably, by fastening the air-cushion system to the pocket firmly, but so as to be detachable by means of snap fasteners.